Mulch is a protective covering material that is typically placed on top of soil and which is used in association with ornamental lawns and gardens. Often the mulch material is placed around trees, shrubs, and bushes to give a pleasing appearance and to prevent the evaporation of water from around the trees, shrubs, or bushes. In general mulch is any of a variety of materials which are used to prevent evaporation of water, protect roots from freezing, and retard the growth of weeds. The mulch material retards the growth of weeds by preventing sunlight from reaching the surface of the ground, which prevents the growth of many plants. Also, the mulch forms a barrier many plant species cannot penetrate. Freezing of roots is prevented because the mulch functions similar to insulation. The mulch prevents evaporation by preventing the surface from being directly contacted by sunlight.
Mulch materials have traditionally been natural materials, such as hay, wood chips, bark, rocks, pea gravel, leaves, and other similar natural plant and mineral. The natural mulch material has generally been effective in preventing evaporation and retarding the growth of some weeds. Natural mulches have further been used because they are attractive and blend in well with natural landscapes. Thus, natural mulches enhance the appearance of a landscape or an ornamental lawn, while functionally preventing evaporation of water and preventing the growth of some weeds. In addition to being functional and attractive, natural mulches are used because they are readily available. Typically, natural mulches are derived from left over plant and mineral materials which have few other uses beyond mulch, consequently natural mulches are further desirable because they are an effective way to usefully dispose of waste plant and mineral materials.
While natural mulches have a number of useful properties, they suffer from a number of drawbacks. One of the primary drawbacks is that natural mulch allows for the growth of too many undesirable plants or weeds, as natural mulch typically does not sufficiently cover an area in a way to prevent the growth of weeds. Also, natural mulch tends to break-down or decompose, meaning it may have a short use life. The decomposition of the natural mulch may also result in offensive odors. Further, some natural mulches tend to dissipate from the areas where they were placed as a result of wind or water runoff carrying the mulch away, as many natural mulches do not have a high specific gravity. Natural mulches are also undesirable because they attract insects.
In response to the problems associated with natural mulches a variety of synthetic mulches and similar products have been developed. One such mulch is made from plastic materials, such as thermoplastics which are typically used to form hard plastic objects such as milk jugs, boat hulls, and pipes. The use of a thermoplastic in the construction of a synthetic mulch, however, suffers from a number of disadvantages. Thermoplastics are not easily colored to look like natural mulches, which is preferred, thus the user of a thermoplastic mulch typically has a limited number of colors to pick from. Also, the thermoplastic mulches do not look realistic or natural, instead they have an artificial look. Mulches made of thermoplastics also suffer because they are generally hard and may have sharp edges. It is known that most thermoplastics are rigid, hard materials so that when a synthetic mulch is made from the thermoplastic material the resulting mulch will provide very little cushioning. This is undesirable because frequently synthetic mulch is placed on areas where children play. Thus, it would be desirable to have a synthetic mulch which has all the characteristics of a natural mulch, but which does not break down, and which is soft and can be easily colored.